Conventional light emitting diode (LED) boards are attached and retained to substrates, such as heat sinks or housings, using mechanical fasteners or features inherent to the substrate. For example, screws or metallic clips are often used that catch an edge or corner of the LED board to hold it in place on an underlying substrate. However, the fastener heads and metallic clips oftentimes extend above the LEDs so as to block light and/or create shadows.